THWACK Meaning of THWACK in English — thwacker , n./thwak/ , v.t.1. to strike or beat vigorously with something flat; whack. n.2. a sharp blow with something flat. [ 1520-30; imit. ] Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012